latte: Interface to 'LattE' and '4ti2'

Back-end connections to 'LattE' (<https://www.math.ucdavis.edu/~latte>)
for counting lattice points and integration inside convex polytopes and
'4ti2' (<http://www.4ti2.de/>) for algebraic, geometric, and combinatorial
problems on linear spaces and front-end tools facilitating their use in the
'R' ecosystem.